WIP: Webpivottables compatibility

Compatibility with http://demo.webpivottable.com/demo-cube.html

Some changes where required for discovery:

• WPT discovers first MDSCHEMA_DIMENSIONS without passing the catalog name (only the cube name, so this should not work when server have two catalogs containing cubes with same name )
• next, it will discovers each hierarchy with MDSCHEMA_HIERARCHIES queries with a restriction on HIERARCHY_NAME. Support for this was added, but we should probably support all restrictions described in the spec
• discovery queries do not pass RestrictionList.HIERARCHY_VISIBILITY == 3 or RestrictionList.MEASURE_VISIBILITY == 3, but since this means "visible or not visible", olapy should just drop this.
• WPT only converts xsd:int to int, regardless of the namespace alias.

The changes for execute are for now the minimal changes so that it looks working.

A patch to processInput method of ZPublisher.HTTPRequest in Zope2 egg is also needed because zope attempt to parse this as a xmlrpc request (the patch is anything to make this condition evaluate to false). I also patched locally to set required CORS headers and reply to OPTIONS request.

This MR has feat/erp5_integration as target branch to only display relevant commits.